1987 grand am problem. help!!!!!

I have a 87 grand am 3.0 v6, the problem i am having is the car has hesitation when going to take off and misses through out the rpm range if i rev it to 3500rpm and hold it loses power and i can slowly press the gas and it wont go higher .if i floor it it does not gain speed or rpm. Also, the biggest problem i have is after a couple miles of driving the cars stalls when i stop at light and will start right back up in park or neutrel but when i put it in drive or reverse it stalls. wiat a couple minutes and it will move agian??????

I have new feul filter 1 year ago and new fuel pump, plugs, wires. I ran the computer and it throws a map sensor code but according to pontiac they dont have a map sensor on my year v6.

please help if you can.

grandam87, I once heard of someone who had a similar problem. When there car would idle, it would drop suspiciously quickly. He went through all kinds of trouble to try and find out waht the problem was, and spent all kind of money in the process, but it turned out, all he needed was a new spark plug. So check them, and see what that turns up.